Starlings put on a display as they gather in murmurations in Gretna, Scotland. It is thought that starlings flock together in large groups for various reasons such as flocking together makes it difficult for predators to target a single bird, it also keeps them warm. They gather over their autumn roosting site just before dusk and perform their acrobatic whirling motions before setting down for the evening. Jeff J Mitchell/Getty

Tens of thousands of starlings start their murmuration, with Criffel mountain in the background, as dusk falls near Gretna Green on the England and Scotland border. The reason for the beautiful spectacle is not definitively known, with theories ranging from a defense mechanism against predators to attracting more birds to join their roost.

A flock of migrating starlings is seen as they perform their traditional dance fly before land to sleep during the sunset near the southern Israeli village of Tidhar in the northern Israeli Negev desert.